This paper presents the implementation and open-loop validation of a cavity emulator for the 1.3 GHz pulsed superconducting-cavity LLRF system under development in our group, for which the real cavity will not be available for an extended period. The emulator runs on an AMC-7Z045 board (Xilinx XC7Z045) and executes the cavity, RF-amplifier, coupler, beam, and detuning models as a pipelined...
High-power klystrons play a critical role in microwave power amplification in radio-frequency (RF) systems for large-scale accelerators, and their operational stability directly affects the long-term reliability of the RF system. To investigate output-power fluctuations, electron reflection, and parasitic oscillations that may occur under load-mismatch conditions, this study takes the output...
This work presents the design and analytical optimization of a high-power, high-efficiency S-band multi-beam klystron (MBK) intended as an RF power source for large-scale scientific facilities. Existing accelerator klystrons demonstrate $50-80 MW$-class peak power near $2.856 GHz$, whereas established MBKs and recent high-efficiency developments operate in the $60-70\%$ electronic-efficiency...
High-efficiency klystrons can significantly reduce the operational costs of particle accelerators. For the low-duty-factor klystrons commonly used in linear accelerators, however, the power consumption of electromagnetic focusing coils remains non-negligible. This work presents the progress of an S-band 50 MW high-efficiency klystron with periodic permanent magnet (PPM) focusing, aiming at...
The reliable operation of high-power RF components, such as input couplers and RF windows, is critical for the Circular Electron Positron Collider (CEPC) project. Prior to installation into the accelerator system, these components require rigorous high-power conditioning to verify their RF performance and thermal stability. However, establishing megawatt-level test facilities is challenging...
For large particle accelerators, the radio-frequency (RF) power source system accounts for a significant portion of total energy consumption. A considerable fraction of the RF power that is not used for particle acceleration is delivered to an absorbing load located at the output of the accelerating structure, where it is converted into heat and dissipated. Recovering this otherwise wasted...
High-voltage pulse modulator is a key device in linear accelerators, serving as the intermediate link that converts power from the power supply into microwave power. According to the CEPC technical design, the linear accelerator requires 236 sets of C-band 80 MW power source systems to supply 5712 MHz/3 μs/100 Hz pulsed power to the accelerating structures. To achieve the target klystron...
The operating voltage of high‑power klystron electron guns reaches the hundred‑kilovolt level. High electric‑field gradient inside the gun readily causes vacuum breakdown and other adverse phenomena, which degrade the voltage withstand capability and service life of the device. Taking a high‑efficiency klystron electron gun as the research object, this paper adopts the Non‑dominated Sorting...
The BEPCII Upgrade (BEPCII-UP) adopts the crab waist collision scheme to significantly enhance luminosity. In this study, lattice design (including the survey, optics parameters, and working point matching) and dynamic aperture optimization for the BEPCII-UP collider ring are carried out using the SAD code. To obtain a sufficient dynamic aperture for injection, a combined-function magnet...
This work presents the design and multi-code simulation of a 10 MW-class L-band (1.3 GHz) multi-beam klystron (MBK) intended as a high-efficiency RF power source for superconducting linear accelerators. The design covers the electron gun, magnetic focusing system, RF interaction structure, output window, and collector. Six low-perveance (0.57 μP) beamlets extracted at a cathode voltage of...
Layout design is a core procedure in particle accelerator development, which guarantees the precise implementation of physics design and underpins full-lifecycle operation and maintenance of the facilities. 2D layout drawings act as fundamental engineering benchmarks for equipment positioning, while 3D layout models provide a global spatial perspective for coordination verification and...
The storage ring vacuum system is a core component ensuring stable beam operation. Its primary function is to provide an ultra‑high‑vacuum environment with ultra‑low gas density for the beam, mitigate scattering losses induced by interactions between the beam and residual gas, and prolong beam lifetime.
The storage ring vacuum system mainly consists of Cr‑Zr‑Cu vacuum chambers,...
Quantum-information observables offer new tools for probing collider events beyond traditional quantities such as cross sections and invariant masses. This work investigates quantum entanglement in top–antitop pairs produced via e⁺e⁻ → tt̄, using spin density matrices generated with the recently developed Density Mode framework within MadGraph5_aMC@NLO. Events were simulated at leading order...
